Break time . . . then a chance for a White Christmas

Thursday, December 20, 2012 at 7:30 am

Thursday update:

Forecast hasn’t changed much over the last 48 hours, Large Low pressure center is dropping down the Coast of BC right now and looking to set up shop off the coast of Washington state for the next few days. As we mentioned the other day, this will send impulse after impulse rotating into the west coast. The Cascades and Sierra Nevada are still looking at a major winter storm. Lots of cold air to work with will keep snow levels low and snow ratios high. Here is a look at the QPF for the next 5 days:

(Click to enlarge)

As you can see, close to 8″ of liquid precipitation might fall along the Sierra Crest which means at even modest ratios of 12:1, there may be 8 feet of snow in places. So if you are planning to drive west to Northern California, be very careful. Or do it today before the worst of it moves in. Here in Utah, we aren’t forecasted to see anywhere near the amount of precipitation as our neighbors to the west. There are two reasons for that: 1. the low pressure system will finally kick inland on Sunday and Monday but weaken significantly as it does so, and 2. this type of long-range, low-resolution QPF forecast does very poorly to pick up on the orographic features of the Great Basin and the Wasatch. Higher resolution models like the NAM will do a much better job forecasting precipitation amounts but we are still out of range of that particular model.

What we will see is two distinct waves, the first one on Sunday will be very weak and will mostly bring just clouds and mountain snow showers to Northern Utah. The second wave moves in on Monday and has much better structure and moisture associated with it and should drop some snowfall in the mountains and even in the valleys. Still very difficult to pinpoint exact timing but Monday appears to be storm day. Strength is also a question as some models have been toying with the idea of splitting the wave as it moves inland. Whether it splits or not, we don’t expect a major snowfall from this system but moderate amounts look likely. So Monday and Christmas day should be great days to ski, Monday a stormy day with snow likely falling. And Tuesday may have some morning snow showers but should clear out for blue bird conditions by the afternoon.

Later next week it looks like the pattern will remain active with another shot for snow late next week (Friday-ish). But still too far off for any details.

Hopefully this Monday system will bring Northern Utah a white Christmas.



Wednesday update:

Blue bird day today with clearing skies and lots of fresh snow! Sunny skies likely for Northern Utah. It has been a long time since we’ve had that, in fact yesterday I commented that I haven’t used my sunny day lenses on my goggles since November. Temps will be cold today but a mild southwest flow will develop over the next few days and warm things up.

Looking at the models trying to figure things out for our next storm. Right now it looks like a weak wave will move into the area on Sunday with a stronger wave on Christmas eve. Still lots of questions as to exact timing and strength. Not going to make any guesses on snow amounts quite yet. Christmas day may see some lingering snow showers. More storms possible later that week. Details on the system below… WSF

Previous . . .

Northern Utah is now wrapping up four days of off and on snow that dropped 15-40″ total in the Wasatch. It’s hard to believe looking at those totals that this storm cycle under-performed, but it did. There was definitely potential for more snow than that — but things didn’t go quite our way. I don’t think too many of us are complaining though. Each of the last four day offered plenty of great snow and faceshots for all! Today was the icing on the cake for me as I got at plenty of totally untracked snow that hasn’t been skied on since last week. Bottomless and fluffy.

Tonight Northern Utah will clear out for the most part with only light orographic snowfall continuing in favored areas like the Cottonwoods. Don’t expect more than a few inches at best from this, but it might be enough to add another fresh layer for tomorrow’s powder hounds. Lake effect snow is still a possibility. The temperature profiles are there to support lake effect, but we are lacking some key atmospheric ingredients so if it were to develop, it would most likely be unorganized and only produce light accumlations southeast of the lake.

Meanwhile, central and southern Utah will continue to see snowfall tonight with heavy accumulations possible. This will help Eagle Point and Brian Head to add to their bases and get terrain open. This snowfall will gradually clear from west to east tomorrow morning.

It’s looking like we will have at least a 4-day break from the action starting tomorrow as a ridge builds over the intermountain west. This ridge will slowly progress eastward as a large Pacific trough drops out of the Gulf of AK and off the northwest coast. The Low associated with this trough will spend a few days spinning its wheels off the coast and sending several strong impulses into the west coast. The Cascades and Sierra Nevada looks to get hammered over the weekend so if you are heading west for the holidays. I suggest you travel with caution and pay close attention to the weather. GFS is particularly strong and paints up to 6″ of QPF for parts of the Sierra and the Cascades from Thursday-Sunday. The Euro is a little less robust and drops 4″ of QPF. Unlike the atmospheric river event that they saw last month, this has plenty of cold air and could drop impressive amounts of snow. Places like Shasta and the mountains west of Tahoe could easily see 4-5 feet of snow. Good news for them as they need to build the bases on the lower parts of the mountains out there.

But what does this mean for us? Well eventually this trough is going to progress inland and when it does, it will provide snow for Utah. It’s looking like right now, the timing will be late Sunday through Monday. There is high confidence in the snow event occurring at this point, but little confidence in the timing or strength details. Latest GFS looked very good, here’s it predicted QPF for the next 8 days:


Christmas Eve and Christmas Day could be good powder days for Utah, and a good chance for a white Christmas in the valleys.

Beyond Christmas there is very little model consensus… Long range CFSv2 forecast indicate we could ridge up for a week or two after the new year– a bit of a “January Thaw”. We’ll see . . .

Hope everybody had fun these last few days!


This entry was posted in Uncategorized on by .